fix saving of shuffleChoices/Answers

scorm-storage was saving the inverse of the choices/answers permutation for MCQ parts.

fixes #313
remove console.logs from numbas.js
update date on copyright notices
update JME tests so they work
start after document.onload to suit IE 9

IE 9 is the last remaining browser that runs scripts in the body before the document is ready.
This commit wraps the Numbas.init code in `$(document).ready(...)` so it only runs when the document is ready.

fixes #315
Starting on using jsdoc to document the code
jsdoc exam.js
update jsdoc
jsdoc: working my way through jme.je
more on jme.js
jme.js done
remove doc directory from repo

It gets regenerated constantly, so not having it makes commits nicer. Maybe it'll get its own repo.
finish documenting jme files
jsdoc: starting on math.js
document vectormath and matrixmath methods
starting to document question.js
start documenting Part
visible: false binding makes sure elements aren't tabbable

when visible: false, set the `disabled` attribute and remove the `tabindex` attribute.

fixes #318
still documenting parts
put loadScript back in

I thought it wasn't needed, but it is!